Glass fibers have hitherto been processed to sized or unsized cakes in the spinning and winding process. These cakes, which have a moisture content of approximately 12% by weight, are then dried in a forced-air oven, precomminuted with guillotine shears and subsequently ground to so-called milled fibers in cross hammer mills.
The disadvantage of this process carried out hitherto is that, after the glas fibers bundle has been cooled and, if appropriate, coated with a size, it is first wound on to a cardboard tube in order then to be dried as so-called wet cake, which has been taken off the winding spindle. After drying, the cardboard tube is removed from the cake by hand and the cake is then extended to form a loose bed and fed to guillotine shears for precomminution. The precomminuted product is then passed into a hammer mill, where it is ground into milled glass fibers.
The milled glass fibers manufactured in this way have the disadvantage of a low apparent density coupled with correspondingly small average lengths.
The object is therefore to provide improved milled glass fibers and an improved and simplified process for the manufacture of these milled glass fibers without the quality of the milled glass fibers being adversely affected.
This object could be achieved by the glass fibers according to the invention and the process according to the invention.